Fluoride fluorescent material particle, composite material, light-emitting device, and method for producing fluoride fluorescent material

Abstract

To improve luminescent properties of Mn-containing fluoride fluorescent materials.SOLUTION: The present invention provides a fluoride fluorescent material particle having a composition represented by A2M(1-n)F6:Mn4+n. The element A is one or more alkali metal elements including K, and the element M is elemental Si, elemental Ge, or a combination of Si and one or more elements selected from the group consisting of Ge, Sn, Ti, Zr, and Hf, and 0<n≤0.1. When a cross section of this fluoride fluorescent material particle is subjected to elemental analysis using an electron beam probe microanalyzer manufactured by JEOL Ltd., model number: JXA-8230, and accompanying software, under conditions in which the accelerating voltage is 15 kV, the irradiation current is 5×10-8 A, the measurement time is 30 ms, the size of the measurement region is 160×160 μm, and the number of measurement points is 400×400 pixels, if the Mn level in the vicinity of the center of the fluoride fluorescent material particle is denoted by Pc, and the Mn level in the vicinity of the surface is denoted by Ps, then Pc≥Ps.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to fluoride phosphor particles, a composite, a light-emitting device, and a method for producing a fluoride phosphor. More specifically, the present invention relates to Mn-containing fluoride phosphor particles, a composite using the phosphor particles, a light-emitting device including the composite, and a method for producing the Mn-containing fluoride phosphor particles.

Background Art

[0002] Regarding fluoride phosphors, particularly manganese (Mn)-containing fluoride phosphors, various studies have been conducted so far from the viewpoint of applying them to wavelength conversion members in, for example, light-emitting diodes.

[0003] Patent Document 1 describes potassium manganyl fluoride represented by the general formula: K2MnF6 and having a diffuse reflectance of 60% or more with respect to light having a wavelength of 550 nm. And it is described that such potassium manganyl fluoride is dissolved in an aqueous hydrofluoric acid solution or the like to produce a fluoride phosphor.

[0004] Patent Document 2 describes a method for producing a color-stable Mn 4+ doped composite fluoride phosphor by causing precipitation from an aqueous solution.

[0005] Patent Document 3 describes using potassium manganyl fluoride having diffraction peaks at positions where the diffraction angle 2θ is 18.2 ± 0.3°, 19.2 ± 0.3°, 26.6 ± 0.3°, 31.8 ± 0.3°, and 42.0 ± 0.3° in a powder X-ray diffraction pattern measured using CuKα rays as a raw material for a fluoride phosphor.

[0006] Patent Document 4 discloses inserting an anode and a cathode into a reaction solution containing a compound containing manganese with a valence less than 4 and / or more than 4 and hydrogen fluoride, and applying a current density of 100 to 1000 A / m between the anode and the cathode. 2A method for producing a hexafluoromanganate(IV) salt, which is characterized by passing a current, is described. Also described is a method for producing a fluoride phosphor using the hexafluoromanganate(IV) salt thus produced.

[0007] Patent Document 5 describes a fluoride phosphor particle having at least one minute recess on its surface.

[0008] Patent Document 6 describes a method for producing a fluoride phosphor represented by the general formula: A2SiF6:Mn (element A is an alkali metal element containing at least potassium). This production method includes a step of preparing an aqueous solution in which element A and fluorine are dissolved in a solvent, and a step of adding a manganese compound that supplies solid silicon dioxide and manganese other than +7 valent to the aqueous solution. In this production method, the addition amount of the manganese compound is in the range where the Mn content in the fluoride phosphor is 0.1 mass% or more and 1.5 mass% or less. In this production method, the fluoride phosphor precipitates in parallel with the dissolution of silicon dioxide in the aqueous solution.

[0009] Patent Document 7 describes a fluoride phosphor powder represented by the composition formula A2M (1-n) F6:Mn 4+ n (0 < n ≦ 0.1; A is one or more alkali metal elements containing at least K; M is one or more elements selected from Si, Ge, Sn, Ti, Zr, and Hf containing at least Si). Taking the distance from the center to the surface of each particle constituting this powder as 100%, the average values of the Mn concentration (mol%) measured at points where the distance from the center is 0%, 25%, 50%, 75%, and 100% are respectively [Mn0], [Mn 25 , [Mn 50 , [Mn 75 , [Mn 100 , then 0 ≦ ([Mn0] + [Mn 25 + [Mn 50 ) / ([Mn 50 + [Mn 75 + [Mn 100 ) ≦ 0.9 holds.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0011] As described above, various studies have been conducted on fluoride phosphors, particularly Mn - containing fluoride phosphors. However, with the spread of light - emitting devices using phosphors and the need for further high - performance improvement of light - emitting devices using phosphors, further improvement of the characteristics of fluoride phosphors is desired.

[0012] The inventors of the present invention have attempted to improve Mn - containing fluoride phosphors, with one of the purposes being to improve the light - emitting characteristics.

Means for Solving the Problems

[0013] The inventor examined the improvement of Mn - containing fluoride phosphors from all viewpoints. As a result of the examination, it was found that the Mn concentration near the center of the particles and the Mn concentration near the surface of the particles in particulate Mn - containing fluoride phosphors seem to be correlated with the light - emitting characteristics. Based on this finding, the inventor of the present invention further conducted studies and completed the invention provided below.

[0014] 1. Fluoride phosphor particles whose composition is represented by the following general formula (1), Using an electron probe microanalyzer manufactured by JEOL Ltd., model number: JXA-8230 and the attached software, with an acceleration voltage of 15 kV, an irradiation current of 5×10 -8 A, a measurement time of 30 ms, a measurement area size of 160×160 μm, and 400×400 pixels for the number of measurement points, by performing elemental analysis on the cross-section of the fluoride phosphor particles, when the Mn level near the center of the fluoride phosphor particles is Pc and the Mn level near the surface of the fluoride phosphor particles is Ps, Fluoride phosphor particles where Pc≧Ps. General formula (1): A2M (1-n) F6:Mn 4+ n In general formula (1), Element A is one or more alkali metal elements containing K, Element M is a single element of Si, a single element of Ge, or a combination of one or more elements selected from the group consisting of Si and Ge, Sn, Ti, Zr, and Hf, 0 < n≦0.1. 2. The fluoride phosphor particles according to 1., Fluoride phosphor particles where the value of Pc - Ps is 4 to 20. 3. The fluoride phosphor particles according to 1. or 2., Fluoride phosphor particles where the value of Pc / Ps is 1.2 to 3.0. 4. The fluoride phosphor particles according to any one of 1. to 3., Fluoride phosphor particles where the value of Pc is 20 to 40. 5. The fluoride phosphor particles according to any one of 1. to 4., Fluoride phosphor particles where the value of Ps is 10 to 20. 6. The fluoride phosphor particles according to any one of 1. to 5., wherein the value Pa of the average Mn level of the cross-section of the fluoride phosphor particles is 14 to 20. 7. The fluoride phosphor particles according to any one of 1. to 6., wherein the region where the Mn level is 31 or more in the cross-section of the fluoride phosphor particles occupies 3 to 15% of the entire particle cross-section. 8. The fluoride phosphor particles according to any one of 1. to 7., in the cross-section of the fluoride phosphor particles, the region where the Mn level is 11 to 30 occupies 70 to 90% of the entire particle cross-section, and the region where the Mn level is 10 or less occupies 0 to 20% of the entire particle cross-section. 9. The fluoride phosphor particles according to any one of 1. to 8., wherein the Mn content based on inductively coupled plasma optical emission spectrometry is 0.5 to 1.5 mass%. 10. A composite comprising the fluoride phosphor particles according to any one of 1. to 9. and a sealing material for sealing the fluoride phosphor particles. 11. A light-emitting device comprising a light-emitting element that emits excitation light and the composite according to 10. that converts the wavelength of the excitation light. 12. A first step of adding KHF2 to an aqueous solution of hydrogen fluoride, stirring to obtain a first liquid, a second step of simultaneously adding a Mn-containing raw material and a Si-containing raw material to the first liquid, stirring to obtain a second liquid, a third step of adding the Mn-containing raw material to the second liquid in one or more portions, stirring to obtain a third liquid, which is a method for producing a fluoride phosphor, wherein the time point of adding the Mn-containing raw material and the raw material containing Si in the second step is set as time 0, and the last time point of adding the Mn-containing raw material in the third step is set as time T. Let the total amount of the Mn-containing raw material introduced in the second step and the third step be M t When By time T / 2, 0.60M t or more of the Mn-containing raw material is introduced. A method for producing a fluoride phosphor. 13. A method for producing a fluoride phosphor according to 12., wherein In the third step, the Mn-containing raw material is introduced in multiple portions. A method for producing a fluoride phosphor. 14. A method for producing a fluoride phosphor according to 12. or 13., wherein The Mn-containing raw material includes K2MnF6. A method for producing a fluoride phosphor. 15. A method for producing a fluoride phosphor according to any one of 12. to 14., wherein The Si-containing raw material includes SiO2. A method for producing a fluoride phosphor.

Advantages of the Invention

[0015] The luminescence characteristics of the fluoride phosphor particles of the present invention are good.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The drawings are for illustrative purposes only. The drawings may not correspond to actual articles.

[0018] In this specification, the notation "X to Y" in the description of a numerical range represents X or more and Y or less, unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% or more and 5 mass% or less".

[0019] In this specification, the term "particle" may mean a single particle (one particle) or a powder which is an aggregate of particles depending on the context.

[0020] <Fluoride phosphor particles> The composition of the fluoride phosphor particles of this embodiment is represented by the general formula (1): A2M (1-n) F6:Mn 4+ n It is represented by. In the general formula (1), Element A is one or more alkali metal elements containing K, Element M is a single Si, a single Ge, or a combination of one or more elements selected from the group consisting of Si and Ge, Sn, Ti, Zr, and Hf, 0 < n ≦ 0.1.

[0021] Using an electron probe microanalyzer manufactured by JEOL Ltd., model number: JXA-8230 and the attached software, with an acceleration voltage of 15 kV, an irradiation current of 5 × 10 -8 A, a measurement time of 30 ms, a measurement area size of 160 × 160 μm, and 400 × 400 pixels for the number of measurement points, by elemental analysis of the cross-section of the fluoride phosphor particles of this embodiment, the Mn level (an index corresponding to the Mn concentration, details are supplemented below) at each location of the cross-section can be obtained. In this measurement, when the Mn level near the center of the fluoride phosphor particles of this embodiment is Pc and the Mn level near the surface of the fluoride phosphor particles is Ps, Pc ≧ Ps.

[0022] The cross-section of the fluoride phosphor particles can be obtained by embedding them using an epoxy resin or the like and then performing cross-section milling. As a method of cross-section milling, ion milling using a cross-section polisher (CP) can be preferably employed. For charge suppression during observation with an electron microscope, it is preferable to apply an osmium coating to the cross-section of the fluoride phosphor particles.

[0023] The Mn level is an index that quantitatively represents the characteristic X-ray intensity of Mn in the measurement area on the surface of the object to be measured, calculated by the measurement using the above analyzer and the analysis by the above software. According to information from JEOL Ltd., although the unit of the Mn level is not mol% or mass%, since the value of the Mn level has a positive correlation with the actual abundance of Mn, the amount of Mn can be discussed based on the value of the Mn level.

[0024] The present inventor has examined the improvement of the Mn-containing fluoride phosphor from all viewpoints. As a result of the examination, it has been found that in the particulate Mn-containing fluoride phosphor, the distribution of Mn, which is the luminescence center, is not uniform. For example, the Mn concentration near the center of the particle may be different from the Mn concentration near the surface of the particle. It has also been found that the non-uniformity of the distribution of Mn in the phosphor seems to be related to the luminescence characteristics. Furthermore, it has been found that the distribution of Mn in the phosphor can be controlled by devising the manufacturing method of the phosphor. Based on these findings, the present inventor has newly manufactured Mn-containing fluoride phosphor particles whose composition is represented by the general formula (1) and in which the Mn concentration Pc near the center is equal to or higher than the Mn concentration Ps near the surface by devising the manufacturing method of the phosphor. Such Mn-containing fluoride phosphor particles exhibit good luminescence characteristics. Although the reason why the luminescence characteristics become good when Pc ≧ Ps is not necessarily clear, one possibility is that crystal defects and heterogeneous phases (phases that do not contribute to luminescence) are less likely to occur near the center of the particles than near the surface. When Mn (luminescence center) exists at a concentration comparable to or higher than that near the surface of the particles near the center of the particles with few crystal defects and heterogeneous phases, even if the total amount of Mn in the particles is the same, it is considered that the luminescence characteristics such as quantum efficiency are enhanced.

[0025] Incidentally, the fluoride phosphor particles of the present embodiment not only have good luminescence characteristics but also have good moisture resistance, that is, they tend to be less susceptible to deterioration due to moisture in the air. Since Pc ≧ Ps, that is, the Mn concentration on the particle surface is less than or equal to the Mn concentration in the particle core, unintended environmental changes, alteration, and detachment of Mn that function as luminescence centers are suppressed, and the moisture resistance may be improved.

[0026] The method for manufacturing the fluoride phosphor particles of the present embodiment will be described later, but it will also be briefly described here. Conventionally, as a method for manufacturing an Mn-containing fluoride phosphor whose composition is represented by the general formula (1), a method of growing crystals of the fluoride phosphor in an aqueous solution in which raw materials are dissolved and obtaining phosphor particles as precipitates has been known. The present inventor considered the reason why the Mn concentration near the center of the particles and the Mn concentration near the surface of the particles may be different in conventional Mn-containing fluoride phosphor particles. As a result of the consideration, it was thought that (i) the rate of crystal growth may be different between the initial stage and the middle and later stages of crystal growth of the fluoride phosphor, and (ii) the ease of incorporation of Mn into the crystal may be different between the initial stage and the middle and later stages of crystal growth. Although the details are unclear, there is a possibility that things like (i) and / or (ii) may occur due to thermodynamic or kinetic factors in supersaturation. Based on such an idea, when growing crystals of a fluoride phosphor in an aqueous solution, the present inventors decided not to introduce the Mn-containing raw material into the aqueous solution all at once, but to introduce the Mn-containing raw material into the aqueous solution in two or more portions. In particular, a large amount of the Mn-containing raw material is introduced into the aqueous solution at a relatively early stage of crystal growth, and a relatively small amount of the Mn-containing raw material is introduced into the aqueous solution or the Mn-containing raw material is not introduced into the aqueous solution after the middle stage of crystal growth. By doing so, the distribution of Mn in the fluoride phosphor particles can be controlled, and fluoride phosphor particles with Pc ≧ Ps can be manufactured.

[0027] The description of the fluoride phosphor particles of this embodiment will be continued.

[0028] (Composition: Regarding General Formula (1)) Element A is one or more alkali metal elements containing K. Specifically, it can be a simple substance of potassium, or a combination of potassium and one or more alkali metal elements selected from lithium (Li), sodium (Na), rubidium (Rb), and cesium (Cs). From the viewpoint of chemical stability, it is preferable that the content ratio of potassium in element A is high (for example, 50 mol% or more of element A is potassium), and it is more preferable that element A is a simple substance of potassium.

[0029] Element M is a simple substance of Si, a simple substance of Ge, or a combination of a simple substance of Si and one or more elements selected from the group consisting of Ge, Sn, Ti, Zr, and Hf. From the viewpoint of chemical stability, it is preferable that the content ratio of silicon in element M is high (for example, 50 mol% or more of element M is silicon), and it is more preferable that element M is a simple substance of silicon.

[0030] In General Formula (1), n may be 0 < n ≦ 0.1, but from the viewpoint of better luminescence characteristics, it is preferably 0.015 ≦ n ≦ 0.04.

[0031] (Pc and Ps, the difference and ratio between them, etc.) In this embodiment, it is sufficient that Pc ≧ Ps. However, by adjusting the values of Pc and Ps themselves (Mn level), the difference between Pc and Ps, the ratio of Pc to Ps, etc., the luminescence characteristics and moisture resistance of the fluoride phosphor particles may be further improved. In particular, when the values of Pc and Ps are sufficiently different, the effects of improving the luminescence characteristics and moisture resistance tend to be clearly obtained.

[0032] Pc is preferably 20 to 40, more preferably 25 to 40, and still more preferably 29 to 31. Ps is preferably 10 to 20, more preferably 10 to 19, and still more preferably 11 to 18. The value of Pc - Ps is preferably 4 to 20, more preferably 11 to 18. The value of Pc / Ps is preferably 1.2 to 3.0, more preferably 1.5 to 3.0, and still more preferably 2.0 to 2.5. Since Ps itself is small and / or Ps is sufficiently smaller than Pc, the reaction between moisture in the air and Mn near the surface of the fluoride phosphor particles is suppressed, so the moisture resistance is considered to be further improved.

[0033] From the viewpoints of good luminescence characteristics and other performances, the amount of Mn in the fluoride phosphor particles is preferably appropriately controlled. In other words, the "average" amount of Mn in the fluoride phosphor particles is preferably within an appropriate numerical range. Specifically, the value of the average value Pa of the Mn level in the cross-section of the fluoride phosphor particles to be subjected to elemental analysis is preferably 14 to 20, more preferably 16 to 20.

[0034] Regarding the "average" amount of Mn in the fluoride phosphor particles, the Mn content rate obtained by ICP emission spectrometry (ICP: initials of Inductively Coupled Plasma) can also be used as an index. Specifically, the Mn content of the fluoride phosphor particles of the present embodiment based on inductively coupled plasma optical emission spectrometry (ICP-OES) is preferably 0.5 to 1.5% by mass, more preferably 0.5 to 1.15% by mass, and even more preferably 0.6 to 1.10% by mass.

[0035] (Regarding the distribution of Mn in the particle cross-section) For the fluoride phosphor particles of the present embodiment, when the cross-section of the particles is subjected to elemental analysis and attention is paid to the Mn level in the vicinity of the center and the surface of the particles, it is sufficient that Pc ≥ Ps. However, by appropriately controlling the distribution of Mn throughout the cross-section, the luminescence characteristics, moisture resistance, etc. tend to be further improved.

[0036] Specifically, in the cross-section of the fluoride phosphor particles that are the subject of elemental analysis, the region where the Mn level is 31 or more preferably occupies 3 to 15% of the entire particle cross-section, more preferably 5 to 12%, and even more preferably 7 to 9%. Also, in the cross-section of the fluoride phosphor particles that are the subject of elemental analysis, the region where the Mn level is 11 to 30 preferably occupies 70 to 90% of the entire particle cross-section, and more preferably 73 to 85%. Furthermore, in the cross-section of the fluoride phosphor particles that are the subject of elemental analysis, the region where the Mn level is 10 or less preferably occupies 0 to 20% of the entire particle cross-section, more preferably 4 to 20%, and even more preferably 7 to 20%. (Just to be on the safe side, the “%” here means area percentage.)

[0037] The numerical ranges of the area ratios regarding the above Mn distribution mean that in the particle cross-section, there are relatively few regions where the Mn concentration is too high or too low, and there are relatively many regions where the Mn concentration is neither too high nor too low, so that the luminescence characteristics, moisture resistance, etc. can be further improved. As the finding of the present inventor, when the region where the Mn level is 31 or more is 15% or less of the entire particle cross-section, the internal quantum efficiency can be further improved. In the fluoride phosphor particles having such a Mn distribution, as already briefly described and to be described in detail later, it can be produced by appropriately controlling the number of times and the timing of introducing the Mn-containing raw material into the aqueous solution when growing the crystals of the fluoride phosphor in the aqueous solution.

[0038] (Particle size distribution) Regarding the fluoride phosphor particles of the present embodiment (more precisely, the phosphor powder which is an aggregate of phosphor particles), due to an appropriate particle size distribution, the light emission characteristics may be further improved or it may be easier to apply to various applications.

[0039] When the cumulative 50% value (median value) in the volume-based particle size distribution curve of the phosphor particles of the present embodiment is D 50 then D 50 is preferably 10 to 50 μm, more preferably 20 to 40 μm. When D 50 is an appropriate value, for example, the internal or external quantum efficiency may be increased.

[0040] From another viewpoint, when the cumulative 50% value (median value) in the volume-based particle size distribution curve of the phosphor particles of the present embodiment is D 50 , the cumulative 10% value in the volume-based particle size distribution curve is D 10 , and the cumulative 90% value in the volume-based particle size distribution curve is D 90 , then the value of (D 90 - D 10 ) / D 50 is preferably 0.60 to 0.89, more preferably 0.77 to 0.84. (D 90 - D 10 ) / D 50 The value can be regarded as an index for quantitatively representing whether the particle size distribution is broad or sharp. A fluoride phosphor in which the value of (D 90 - D 10 ) / D 50 is not too large, that is, a fluoride phosphor having an appropriately sharp particle size distribution, tends to have excellent light emission characteristics because it does not contain many ultrafine particles or coarse particles that tend to reduce the quantum efficiency. As the findings of the present inventors, as described below, in the production of the fluoride phosphor, by appropriately controlling the timing and number of times of introducing the Mn-containing raw material into an aqueous solution, the value of (D 90 -D 10 ) / D 50 may be preferably controlled. And, by appropriately controlling the value of (D 90 -D 10 ) / D 50 the performance such as the light emission characteristics may be further improved.

[0041] The particle size distribution curve based on volume can be obtained through measurement by the laser diffraction scattering method. For details of the measurement method, refer to the examples described below.

[0042] <Composite and Light Emitting Device> The composite of the present embodiment includes the above-described fluoride phosphor and a sealing material that seals the fluoride phosphor. Further, the light emitting device of the present embodiment includes a light emitting element that emits excitation light and the above-described composite that converts the wavelength of the excitation light.

[0043] Hereinafter, an example of the composite and the light emitting device will be described with reference to FIG. 1.

[0044] FIG. 1 is a schematic diagram of the light emitting device 1. The light emitting device 1 includes a composite 10 and a light emitting element 20. The composite 10 is provided in contact with the upper part of the light emitting element 20. The light emitting element 20 is typically a blue LED. Terminals are present below the light emitting element 20. When the terminals are connected to a power source, the light emitting element 20 can emit light. The excitation light emitted from the light emitting element 20 is wavelength-converted by the composite 10. When the excitation light is blue light, the blue light is wavelength-converted to red light by the composite 10 containing the phosphor powder.

[0045] The composite 10 can be composed of the above-described phosphor powder and a sealing material that seals the phosphor powder. As the sealing material, for example, various curable resin materials (materials curable by heat and / or light) can be used. Any curable resin material can be used as long as it is sufficiently transparent and can obtain the optical properties required for displays and lighting devices. As the sealing material, for example, silicone resin materials can be mentioned. For silicone resin materials, curable ones are supplied by companies such as Toray Dow Corning and Shin-Etsu Chemical. Silicone resin materials are preferable from the viewpoints such as high transparency and excellent heat resistance. In addition, epoxy resin materials, urethane resin materials, etc. can also be mentioned as the sealing material. The amount of the phosphor powder particles in the composite 10 is, for example, 10 to 70% by mass, preferably 25 to 55% by mass.

[0046] The size and shape of the light-emitting element 20 are not particularly limited. Depending on the use of the light-emitting device 1, the light-emitting element 20 can have any size and shape.

[0047] <Manufacturing method of fluoride phosphor> As already briefly described, fluoride phosphor particles with Pc ≧ Ps can be manufactured by appropriately controlling the timing and number of times of introducing the Mn-containing raw material into the aqueous solution when growing the crystals of the fluoride phosphor in the aqueous solution to obtain phosphor particles.

[0048] Fluoride phosphor particles with Pc ≧ Ps can be specifically manufactured through a series of steps including the following first to third steps. In this series of steps, usually, in the second and third steps, the particles (crystals) of the fluoride phosphor particles gradually precipitate. In other words, it is preferable to appropriately adjust the concentration (usage amount) of each raw material so that the aqueous solution becomes saturated in the second step. The preferable concentration (usage amount) of each raw material can refer to, for example, the examples described later. ·The first step of adding KHF2 to an aqueous solution of hydrogen fluoride and stirring to obtain a first liquid ·The second step of simultaneously adding an Mn-containing raw material and an Si-containing raw material to the first liquid and stirring to obtain a second liquid · A third step of obtaining a third liquid by adding a Mn-containing raw material to the second liquid in one or more portions and stirring

[0049] In the above series of steps, Taking the time point of adding the Mn-containing raw material and the raw material containing Si in the second step as time 0, Taking the last addition time point of the Mn-containing raw material in the third step as time T, Let the total amount of the Mn-containing raw material added in the second step and the third step be M t When this is done, By time T / 2, preferably 0.60M t or more, more preferably 0.70M t or more, still more preferably 0.80M t or more of the Mn-containing raw material is added, fluoride phosphor particles with Pc≧Ps can be produced. That is, in the growth process of the crystal particles of the fluoride phosphor in the aqueous solution, by adding a relatively large amount of the Mn-containing raw material to the aqueous solution at a relatively early stage, fluoride phosphor particles with Pc≧Ps can be produced.

[0050] The concentration of the aqueous solution of hydrogen fluoride in the first step is preferably 40% by mass or more, more preferably 55% by mass or more. The concentration of the aqueous solution of hydrogen fluoride may be the saturation concentration. The input amount of KHF2 in the first step can be, for example, 0.05 - 0.08 mol, preferably 0.0587 - 0.0726 mol, more preferably 0.0615 - 0.0689 mol, per 1 mol of HF in the aqueous solution. The total amount of Mn atoms in the Mn-containing raw material added in the second and third steps may be appropriately adjusted in consideration of the value of n in the general formula (1). The total amount of Mn atoms can be, for example, preferably 0.01 - 0.10 mol, more preferably 0.05 - 0.09 mol, per 1 mol of Si atoms in the Si-containing raw material in the second step.

[0051] Examples of raw materials containing Mn include hexafluoromanganates, permanganates, oxides (excluding permanganates), fluorides (excluding hexafluoromanganates), chlorides, sulfates, and nitrates. Among them, fluorides are preferred because Mn can be efficiently substituted for Si sites in the fluoride phosphor, and good luminescence characteristics can be obtained. Among the fluorides, hexafluoromanganates are preferred. Examples of hexafluoromanganates include Na2MnF6, K2MnF6, Rb2MnF6, MgMnF6, CaMnF6, SrMnF6, BaMnF6, etc. In particular, K2MnF6 is preferred because it can simultaneously supply fluorine atoms and potassium atoms (potassium atoms correspond to element A in the general formula (1)) that constitute the fluoride phosphor in addition to Mn. Examples of raw materials containing Si include silicon dioxide, K2SiF6, H2SiF6, etc. Silicon dioxide is preferred as the Si-containing raw material in view of the performance of the final fluoride phosphor particles and the availability of the raw material.

[0052] In addition, when manufacturing the fluoride phosphor, for matters not specified above, known techniques may be referred to or appropriate trial and error may be carried out. Examples of known techniques for reference include the aforementioned Patent Document 6 (International Publication No. 2017 / 057671).

[0053] The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Examples

[0054] Embodiments of the present invention will be described in detail based on examples and comparative examples. Just to be clear, the present invention is not limited only to the examples.

[0055] <Preparation of raw materials> The following raw materials were prepared. HF: An aqueous solution with a concentration of 55% by mass manufactured by Stella Chemifa Corporation K2MnF6: Manufactured by Stella Chemifa Corporation (K2MnF6 may be abbreviated as "KMF" hereinafter.) KHF2: Special grade reagent manufactured by Fujifilm Wako Pure Chemical Corporation SiO2: FB-50R manufactured by Denka Company Limited

[0056] <Example 1: Production of Fluoride Phosphor Particles> Fluoride phosphor particles were produced according to the following procedure. (First step) At room temperature, 2100 mL of an HF aqueous solution with a concentration of 55% by mass was placed in a Teflon (registered trademark) beaker, 330 g of KHF2 was added, and the mixture was stirred well using a magnetic stirrer. Thereby, a uniform solution (the first solution) was obtained. (Second step) The above beaker was immersed in the antifreeze in a cooling bath containing antifreeze, and cooling was started while continuing stirring. Then, when the first solution reached -7°C, 72 g of SiO2 and 8.53 g of KMF were simultaneously added to the first solution. The time of this addition was set as time t = 0. Thus, the second solution was obtained. (Third step) While continuing stirring and cooling, 4.27 g of KMF was sequentially added to the second solution at t = 90 s, 2.13 g of KMF at t = 180 s, and 1.07 g of KMF at t = 270 s. Then, stirring was terminated at t = 1500 s (25 minutes). (Post-treatment) After the stirring in the third step was completed, the solution was allowed to stand to sufficiently precipitate the yellow solid content. Then, the supernatant was removed, the yellow solid content was washed with hydrofluoric acid with a concentration of about 24% by mass, and then washed with methanol. The washed solid content was filtered to separate and recover the solid content, and further, the residual methanol was evaporated and removed by a drying treatment. After the drying treatment, using a nylon sieve with a mesh size of 75 μm, only the yellow powder that passed through this sieve was classified and recovered. As described above, 233.08 g of the fluoride phosphor particles of Example 1 were obtained.

[0057] In the above procedure, the time T at the last addition of the Mn-containing raw material in the third step is 270 s. Therefore, T / 2 = 135 s. And the amount of KMF added by the time T / 2 = 135 s is 8.53 g + 4.27 g = 12.80 g. Also, the total amount M of KMF added in the second and third steps t is 8.53 g + 4.27 g + 2.13 g + 1.07 g = 16.00 g. From the calculation of 12.80 g / 16.00 g, it can be seen that in Example 1, 0.80 M t of the Mn-containing raw material was added by the time T / 2 = 135 s.

[0058] <Example 2: Production of Fluoride Phosphor Particles> Fluoride phosphor particles were produced according to the following procedure. (First Step) A uniform solution (the first solution) was obtained in the same manner as in the first step of Example 1. (Second Step) The beaker containing the first solution was immersed in the antifreeze liquid in a cooling tank, and cooling was started while continuing stirring. When the first solution reached -7°C, 72 g of SiO2 and 12.00 g of KMF were simultaneously added to the first solution. This addition time was set as time t = 0. In this way, the second solution was obtained. (Third Step) While continuing stirring and cooling, 6.02 g of KMF was added to the second solution at t = 90 s, 3.01 g of KMF at t = 180 s, 1.51 g of KMF at t = 270 s, 0.75 g of KMF at t = 360 s, 0.38 g of KMF at t = 450 s, 0.20 g of KMF at t = 540 s, and 0.10 g of KMF at t = 630 s, sequentially. And the stirring was terminated at the time point of t = 1500 s (25 minutes). (Post-treatment) The same post-treatment as in Example 1 was performed. And 241.69 g of the fluoride phosphor particles of Example 2 were obtained.

[0059] In the above procedure, the time T at the last input of the Mn-containing raw material in the third step is 630 s. Therefore, T / 2 is 315 s (5 minutes and 15 seconds). And the amount of KMF input by the time T / 2 = 315 s is 12.00 g + 6.02 g + 3.01 g + 1.51 g = 22.54 g. Also, the total amount M of KMF input in the second and third steps t is 12.00 g + 6.02 g + 3.01 g + 1.51 g + 0.75 g + 0.38 g + 0.20 g + 0.10 g = 23.97 g. From the calculation of 22.54 g / 23.97 g, it can be seen that in Example 2, 0.94 M t of the Mn-containing raw material was input by the time T / 2 = 315 s.

[0060] <Comparative Example 1: Production of Fluoride Phosphor Particles> Fluoride phosphor particles were produced by the following procedure. All procedures were carried out while cooling. (First Step) A uniform solution (the first solution) was obtained in the same manner as in the first step of Example 1. (Second Step) The beaker containing the first solution was immersed in the antifreeze liquid in a cooling tank containing antifreeze liquid, and cooling was started while continuing stirring. When the first solution reached -7 °C, 72 g of SiO2 and 4.00 g of KMF were simultaneously input into the first solution. This input time was set as time t = 0. In this way, the second solution was obtained. (Third Step) While continuing stirring and cooling, 4.00 g of KMF was sequentially input into the second solution at t = 45 s, 4.00 g of KMF at t = 90 s, and 4.00 g of KMF at t = 135 s. And the stirring was terminated at the time point of t = 1500 s (25 minutes). (Post-treatment) The same post-treatment as in Example 1 was carried out. And 234.75 g of the fluoride phosphor particles of Comparative Example 1 were obtained.

[0061] In the above procedure, the time T at the last input of the Mn-containing raw material in the third step is 135 s. Therefore, T / 2 is 67.5 s. And the amount of KMF input by the time T / 2 = 67.5 s is 4.00 g + 4.00 g = 8.00 g. Also, the total amount M of KMF input in the second and third steps t is 4.00 g + 4.00 g + 4.00 g + 4.00 g = 16.00 g. From the calculation of 8.00 g / 16.00 g, it can be seen that in Example 2, 0.50 M t of the Mn-containing raw material was input by the time T / 2 = 67.5 s.

[0062] <Analysis of the elemental composition of the entire fluoride phosphor particles> Regarding the fluoride phosphor particles obtained in Example 1, 2 and Comparative Example 1, the elemental compositions of K, Si and Mn were analyzed by ICP emission spectrometry, and the elemental composition of F was analyzed by ion chromatography. As a result of the analysis, in the fluoride phosphor particles obtained in Example 1, 2 and Comparative Example 1, the molar ratios of K, Si and F were all in the stoichiometric ratio of 2:1:6 derived from the chemical formula K2SiF6. From this, it was determined that K2SiF6 crystals were obtained in Example 1, 2 and Comparative Example 1. The amount of Mn in the fluoride phosphor particles is shown in Table 1 below.

[0063] <Elemental analysis of the particle cross-section> The following procedure was carried out. (Cross-section processing of the particles) First, the fluoride phosphor particles were embedded using an embedding epoxy resin known as "G2 epoxy". Then, the cross-section of the fluoride phosphor particles was exposed by ion milling using a cross-section polisher (CP). After that, the cross-section of the fluoride phosphor particles was coated with osmium. (Elemental analysis) Regarding the cross-section of the fluoride phosphor particles embedded in the cured epoxy resin prepared above, elemental analysis was performed using an electron probe microanalyzer manufactured by JEOL Ltd., model number: JXA-8230 and the attached software. And data on the Mn level at each measurement point was obtained. The details of the measurement conditions were as follows. Acceleration voltage: 15 kV Irradiation current: 5×10 -8 A Measurement time: 30 ms Size of the measurement area: 160×160 μm Number of measurement points: 400×400 pixel (From the size of the above measurement area and the number of measurement points, in this example, the Mn level was measured with a 0.4×0.4 μm area as 1 pixel.)

[0064] For reference, Figure 2 shows the elemental mapping image of the cross-section of the fluoride phosphor particles of Example 1, Figure 3 shows the elemental mapping image of the cross-section of the fluoride phosphor particles of Example 2, and Figure 4 shows the mapping image of the Mn level of the cross-section of the fluoride phosphor particles of Comparative Example 1. In each figure, the straight dashed lines numbered 1 to 5 drawn on the part of the fluoride phosphor particles are for the following data analysis. The dashed lines are drawn from one end to the other end of the particle cross-section (the ends of the particle cross-section correspond to the surface of the particle before cutting). Here, the "ends" of the particle cross-section were determined by whether the Mn level was 5 or less or 6 or more. That is, the part with an Mn level of 5 or less was regarded as the cured product of the embedding epoxy resin, and the part with an Mn level of 6 or more was regarded as the fluoride phosphor particles. ※ Supplementary note · Reason for determining the "ends" of the particle cross-section by whether the Mn level is 5 or less or 6 or more: In elemental mapping, even in parts that are clearly not particles (parts that clearly correspond to the embedding epoxy resin), there were pixels with a non-zero Mn level (maximum 5). ·For the convenience of analysis, since the dashed lines 1 to 5 cannot be drawn obliquely, in the elemental mapping image, first, a particle was found where a straight line could be drawn from one end to the other end of the particle, and the straight line passed through the center of the particle as much as possible. Then, a straight line (the straight dashed lines 1 to 5) was drawn from one end to the other end of the particle.

[0065] (Calculation of Pc, Ps, etc. by analysis of the obtained data) It was carried out according to the following procedure. (1) From the data obtained by elemental analysis, the values of the Mn level at the measurement points on the dashed lines 1 to 5 in FIGS. 2 to 4 were extracted. (2) For each of the dashed lines 1 to 5, the average values ps1 to ps5 of the Mn level for 10 pixels at one end were calculated. And the arithmetic mean value ps av was calculated. Also, for the other ends of the dashed lines 1 to 5, the average values ps’1 to ps’5 of the Mn level for 10 pixels at the ends were calculated. And the arithmetic mean value ps’ av was calculated. (3) The value calculated by the calculation of (ps av + ps’ av ) / 2 was adopted as Ps, that is, the Mn level near the surface of the fluoride phosphor particles. (4) For each of the dashed lines 1 to 5, the average values pc1 to pc5 of the Mn level for 10 pixels near the midpoint (5 pixels on each side of the midpoint) were calculated. And the arithmetic mean value of pc1 to pc5 was adopted as Pc, that is, the Mn level near the center of the fluoride phosphor particles. (5) Based on Ps obtained in (3) and Pc obtained in (4), their differences, ratios, etc. were calculated.

[0066] (Analysis of the distribution of Mn in the particle cross-section) Using the software Excel (trade name) of Microsoft Corporation, in the cross-section of each particle, · The number of pixels with an Mn level of 0 to 10, · The number of pixels with an Mn level of 11 to 20, · The number of pixels with an Mn level of 21 - 30, · The number of pixels with an Mn level of 31 - 40, · The number of pixels with an Mn level of 51 - 60, · The number of pixels with an Mn level of 61 - 70, · The number of pixels with an Mn level of 71 - 80, · The number of pixels with an Mn level of 81 - 90, and, · The number of pixels with an Mn level of 91 - 100, were counted. Based on the counting results, the ratio (area ratio) of the region with an Mn level of 31 or more, the ratio (area ratio) of the region with an Mn level of 11 - 30, and the ratio (area ratio) of the region with an Mn level of 10 or less in the cross - section of the fluoride phosphor particles were determined respectively. Also, based on the counting results, the average value Pa of the Mn level of the cross - section of the fluoride phosphor particles was determined. (Pa = the sum of the Mn levels of all pixels in the particle cross - section / the total number of all pixels in the particle cross - section)

[0067] Supplement: Similar to the calculation of the above - mentioned Ps, in the analysis of the Mn distribution here, for the "ends" of the particle cross - section, whether the Mn level is 5 or less or 6 or more was used as the criterion. That is, in the vicinity of the ends of the particle cross - section, the part with an Mn level of 5 or less was not counted considering it as the cured product of the embedding epoxy resin, and the part with an Mn level of 6 or more was counted considering it as the fluoride phosphor particles. However, since there are some pixels with an Mn level of 5 or less even in a part of the region that has entered sufficiently into the interior of the particle from the end in the particle cross - section, those pixels were counted.

[0068] For the above - mentioned analysis content, to assist the reader of this specification in understanding, a part of the cross - section of the fluoride phosphor particles in Example 1, showing the Mn level of each pixel (a part of the Excel screenshot) is shown in FIG. 5. The right side in the figure is the end.

[0069] <Measurement of particle size distribution> Weighed 30 mL of ethanol into a 50 mL beaker and added 0.03 g of fluoride phosphor particles thereto. Next, the container was set in a homogenizer (manufactured by Nippon Seiki Co., Ltd., product name US-150E) whose output had been adjusted to "Altitude: 100%" in advance, and pretreatment was carried out for 3 minutes. In this way, a dispersion of fluoride phosphor particles was obtained. Using a laser diffraction / scattering particle size distribution analyzer (manufactured by Microtrac Bel Co., Ltd., product name MT3300EXII), a volume-based particle size distribution curve was obtained for the dispersion thus prepared. Then, from the obtained curve, D 50 , D 10 and D 90 were determined.

[0070] <Evaluation of luminescence characteristics> A standard reflector (manufactured by Labsphere, product name Spectralon) with a reflectivity of 99% was set in the side opening (φ10 mm) of an integrating sphere (φ60 mm). Monochromatic light spectrally separated to a wavelength of 455 nm from a light-emitting light source (Xe lamp) was introduced into this integrating sphere by an optical fiber. Then, the spectrum of the reflected light was measured by a spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., product name QE-2000). At this time, the number of excitation photons (Qex) was calculated from the spectrum in the wavelength range of 450 to 465 nm. Next, a concave cell filled with fluoride phosphor particles so that the surface was smooth was set at the opening of the integrating sphere. Then, the fluoride phosphor particles were irradiated with monochromatic light having a wavelength of 455 nm. Then, the spectra of the excitation reflected light and fluorescence were measured by a spectrophotometer. From the obtained spectral data, the number of excitation reflected photons (Qref) and the number of fluorescence photons (Qem) were calculated. The number of excitation reflected photons was calculated in the same wavelength range as the number of excitation photons, and the number of fluorescence photons was calculated in the wavelength range of 465 to 800 nm. From the three types of photon numbers obtained, the following three characteristics were calculated. · Absorption rate (%): {(Qex - Qref) / Qex} × 100 ·Internal quantum efficiency (%): {Qem / (Qex - Qref)} × 100 ·External quantum efficiency (%): (Qem / Qex) × 100

[0071] <Evaluation of moisture resistance> 3 g of fluoride phosphor particles placed on a watch glass were put into a small high-temperature and high-humidity chamber (model: IW222) manufactured by Yamato Scientific Co., Ltd., and an exposure degradation test was carried out under the conditions of 60 °C, 90% RH, and 25 hours. Before and after the exposure degradation test, the external quantum efficiency was measured. Then, the moisture resistance was evaluated by the formula of {(External quantum efficiency after the test) / (External quantum efficiency before the test)} × 100 (%). The closer the value calculated by this formula is to 100, the better the moisture resistance. Note that the method for measuring the external quantum efficiency here was carried out as described in the above <Evaluation of luminescence characteristics>.

[0072] Various information is summarized and shown in Tables 1 and 2.

[0073]

Table 1

[0074]

Table 2

[0075] As shown in the above table, the internal quantum efficiency and external quantum efficiency of the fluoride phosphor particles of Examples 1 and 2 where Pc ≥ Ps (Pc - Ps is 0 or more) were better than those of the fluoride phosphor particles of Comparative Example 1 where Pc < Ps (Pc - Ps is negative). That is, the fluoride phosphor particles of Examples 1 and 2 where Pc ≥ Ps showed good luminescence characteristics. Also, from the difference in the manufacturing methods between Examples 1 and 2 and Comparative Example 1, it is understood that appropriately adjusting the timing of the input of the Mn-containing raw material when growing the crystals of the fluoride phosphor in an aqueous solution can be a key point for manufacturing fluoride phosphor particles where Pc ≥ Ps.

[0076] In addition to good luminescence characteristics, the fluoride phosphor particles of Example 1 showed better moisture resistance than the fluoride phosphor particles of Example 2. It is presumed that this result regarding moisture resistance is related to the fact that the amount of Mn present near the particle surface was smaller in the fluoride phosphor particles of Example 1. That is, it is presumed that in the fluoride phosphor particles of Example 1, since the amount of Mn present on the particle surface was smaller than that in the fluoride phosphor particles of Example 2, hydrolysis of Mn was suppressed even in an environment of 60 °C and 90% RH, and a decrease in the external quantum efficiency was suppressed.

Description of Signs

[0077] 1 Light-emitting device 10 Composite 20 Light-emitting element

Claims

1. Fluoride phosphor particles having a composition represented by the following general formula (1), wherein Pc ≥ Ps. Using an electron probe microanalyzer manufactured by JEOL Ltd., model number: JXA-8230 and the attached software, at an acceleration voltage of 15 kV, an irradiation current of 5×10 －８ A, measurement time of 30 ms, measurement area size of 160×160 μm, and number of measurement points of 400×400 pixel, by elemental analysis of the cross-section of the fluoride phosphor particles, when the Mn level near the center of the fluoride phosphor particles is Pc and the Mn level near the surface of the fluoride phosphor particles is Ps Fluoride phosphor particles, where Pc ≥ Ps. General formula (1): A ２ M （１－ｎ） F ６ : Mn ４＋ ｎ In general formula (1), element A is one or more alkali metal elements containing K, element M is a single Si, a single Ge, or a combination of one or more elements selected from the group consisting of Si and Ge, Sn, Ti, Zr, and Hf, 0 < n ≤ 0.

1.

2. The fluoride phosphor particles according to Claim 1, wherein the value of Pc - Ps is 4 to 20.

3. The fluoride phosphor particles according to Claim 1 or 2, wherein the value of Pc / Ps is 1.2 to 3.

0.

4. The fluoride phosphor particles according to Claim 1 or 2, wherein the value of Pc is 20 to 40.

5. The fluoride phosphor particles according to Claim 1 or 2, wherein the value of Ps is 10 to 20.

6. The fluoride phosphor particles according to Claim 1 or 2, wherein the value of Pa, which is the average value of the Mn level in the cross-section of the fluoride phosphor particles, is 14 to 20.

7. The fluoride phosphor particles according to Claim 1 or 2, wherein in the cross-section of the fluoride phosphor particles, the region where the Mn level is 31 or more occupies 3 to 15% of the entire particle cross-section.

8. The fluoride phosphor particles according to Claim 1 or 2, wherein in the cross-section of the fluoride phosphor particles, the region where the Mn level is 11 to 30 occupies 70 to 90% of the entire particle cross-section, and the region where the Mn level is 10 or less occupies 0 to 20% of the entire particle cross-section.

9. The fluoride phosphor particles according to Claim 1 or 2, wherein the Mn content based on ICP emission spectrometry is 0.5 to 1.5 mass%.

10. A composite comprising the fluoride phosphor particles according to Claim 1 or 2 and a sealing material for sealing the fluoride phosphor particles.

11. A light-emitting device comprising a light-emitting element that emits excitation light and the composite according to Claim 10 that converts the wavelength of the excitation light.

12. Into an aqueous solution of hydrogen fluoride, KH F ２ is added and stirred to obtain a first liquid in a first step, and A second step of simultaneously introducing a Mn-containing raw material and a Si-containing raw material into the first liquid, stirring to obtain a second liquid, A third step of introducing the Mn-containing raw material into the second liquid in one or multiple portions, stirring to obtain a third liquid. A method for manufacturing a fluoride phosphor containing Taking the time point when the Mn-containing raw material and the raw material containing Si are introduced in the second step as time 0, and taking the last introduction time point of the Mn-containing raw material in the third step as time T, Let the total amount of the Mn-containing raw material input in the second step and the third step be M ｔ When this is the case By time T / 2, Mn-containing raw materials of 0.60 M or more are introduced. ｔ A method for producing a fluoride phosphor, in which Mn-containing raw materials of 0.60 M or more are introduced by time T / 2.

13. A method for manufacturing a fluoride phosphor according to claim 12, In the third step, a method for manufacturing a fluoride phosphor in which a Mn-containing raw material is introduced in multiple portions.

14. A method for manufacturing a fluoride phosphor according to claim 12 or 13, The Mn-containing raw material is K ２ MnF ６ A method for producing a fluoride phosphor, which comprises

15. A method for manufacturing a fluoride phosphor according to claim 12 or 13, The Si-containing raw material is SiO ２ and is a method for producing a fluoride phosphor.

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